Here's a script I wrote to integrate with a REST API, stripped down a little to make it more generic. It's a token authenticated service, where if you set a value to the API key it will login and request a token it can use to refresh. I think that's similar to what you would need to do, or you could manually provide the token to the script.

You will want to be using the latest version of Mango. We recently added some HTTP utilities to the scripting data source that this script hinges on, and we just made the release that contains them. Here's the git issue describing the feature (it may not be fully documented yet) https://github.com/infiniteautomation/ma-core-public/issues/1094

Alternatively, it's possible you may be able to get what you want out of an HTTP Json Retriever if you can set your session token such that it doesn't time out and is a static header for the data source.

I wonder if something has gone awry in your upgrade process. I just updated a Mango to the version you have and when I run print(HttpBuilder) in a Scripting data source I get a description of the utility.

Is it possible that you have more than one mango-X.Y.Z.jar in your Mango/lib/ directory, or have one elsewhere on the classpath? How did you update?

There were some errors (can't find jar or smth) on updating process so I just extracted m2m2-core-3.2.2.zip into my Mango directory. And yes, there were two files - mango-3.2.1.jar and mango-3.2.2.jar, so I deleted 3.2.1 and now it started with HttpBuilder.
Thanks! Going to analyze your script..

You may consider placing the m2m2-core-3.2.2.zip into your Mango/ directory again and then simply restart Mango. It will automatically perform an upgrade if there is a new core zip in the Mango/ directory. It's possible there were other JARs update and you'd have duplicates of those too, which would produce uncertain results.